Sawdust on stacked wood
Should sawdust be cleaned off before stacking and drying? October 15, 2001
As I cut up lumber on my new bandsaw, there is sawdust left on the wood. Do I just stack and dry and not worry or should I clean off the sawdust first? I saw mostly softwoods for framing, but I don't want my wood getting stained or moldy.
If there is a large amount of sawdust left, you have a problem with the set in your bands. If it is warm to the touch and packed tight on the board, there is not enough set. Raise your set a few thousandths. If it is loose on the board, then you have too much set. I prefer a little extra set in my bands. Just one or two thousandths. If it is loose on the boards, the wind will take it away. If it is packed, you will tend to have problems trying to dry it. The sawdust will hold the moisture in and will mold the wood.
You should clean off all the dust you can, as I have found it slows down the drying time and consistency.
As the boards come off the mill, I usually stack them on a temporary pile before they go to be properly piled and stickered. I use the top edge to scrape off most of the sawdust as I slide a new board onto the pile. This gets most of it.
I have the same thing when I mill and usually the normal handling of the boards gets most of it off. I don't worry unless the sawdust is really thick from flatstacking or something, unless I'm cutting black oak--it seems to stain if you don't get the dust off. I've had stacks of cedar stickered and watched the sawdust fly off as the afternoon breeze blows through. It will dry the dust and blow it away with no harm done if the wind and heat will co-operate.
I experience excessive sawdust buildup on the lumber I'm cutting, also. I've experimented with different sets with my blades and haven't seemed to nail down the proper set. What set do you guys run for cutting softwoods, mostly southern pine and cypress? I'm using 1 1/4 Woodmizer blades.
From contributor T:
I use a 21 thou set and a 13 degree rake. You might try speeding up your cutting speed. If the tooth is more aggressive, it takes more of a curl of wood instead of a powder and can expel it better. I've found that some of those problems are solved by something that seems to have nothing to do with it.
What are you sawing with a rake of 13 degrees? Wouldn’t that be a bit much for hardwood?
The person I saw with tends to have some way of knocking most of the dust off boards as she offbears. Lots of times she lets the board wack the bed of the mill a smart one. Or if she is on the outside end of the edger, she’ll grab the off edge of the board and flip it on the outfeed rollers. She grades the boards as they come off so she’s going to look at both sides.
I keep a big brush handy while I’m sawing grade lumber to brush off the top face of the cant so I can grade it so one side is normally already dusted. We put the dusted side down in the stack and then use a broom to sweep the topside – once the layer is full.
As we are not drying the lumber, we are dusting it so we can grade it better and to make it look better to the broker.
From contributor T:
13 degrees may be a bit much for hardwoods but I don't cut as much hardwood as you folks do. I am cutting southern yellow pine and cypress mostly, a fair amount of red cedar and sporadic runs of water oak, laurel oak, bays and gums. It works good on those hardwoods and excellent on those softwoods. Live oak is a different story.
A lot of rake would be pretty tough on harder woods of any kind. Even some SYP doesn't get along with it too good.
I found that you can reduce the amount of sawdust left on the boards by two things.
1. Increase your feed rate until the sawdust is gritty or curled up.
2. Slow the band speed down so teeth bite in more to form curl in sawdust. The gullet of the tooth will carry sawdust out of the cut without so much spill-out.
Contributor T is about correct on set and hook angle. I find that .022 to .024 works good on the woods we have in the NW for set per side. For hook angle, I use 10 for hardwoods and up to 15 degrees for fir.
From the original questioner:
As far as blade sets and hook angle, I'll have to start to study that. I'm just using the blades that got sent to me Ultra Blades 7/8 x .041 and honestly, I have no idea what that means. Also speed of blade and feed I'll have to work on.
From contributor T:
On your blade, 7/8 is the distance from tip to tip of the teeth. .041 is the thickness of the steel that makes the band. Common thicknesses you will run into are .035, .042, .055 and quite a few others. The thicker the blade the harder you can saw and the more horsepower it will stand. Just a rule of thumb.